Bioerodible silicon-based compositions for delivery of therapeutic agents

ABSTRACT

The invention comprises a composition comprising a bioerodible porous silicon-based carrier material wherein the carrier material carries at least one large molecule therapeutic agent and at least one amorphous sugar, optionally further comprising a crystallization inhibitor. The composition may be used in vitro or in vivo to deliver the therapeutic agent, preferably in a controlled fashion over an intended period of time such as over multiple days, weeks or months. The composition may be used for treating or preventing conditions of a patient such as chronic diseases.

RELATED APPLICATIONS

This application in a continuation of U.S. patent application Ser. No.14/211,170, filed Mar. 14, 2014, which claims the benefit of priority toU.S. Provisional Patent Application Ser. No. 61/798,324, filed Mar. 15,2013, the contents of each of which are hereby incorporated by referenceherein in their entirety.

BACKGROUND

There has been considerable interest within the pharmaceutical industryin the development of dosage forms which provide controlled release oftherapeutic agents over a period of time. Releasing an active substancein this way can help to improve bioavailability and ensure thatappropriate concentrations of the agent are provided for a sustainedperiod without the need for repeated dosing. In turn, this also helps tominimize the effects of patient non-compliance which is frequently anissue with other forms of administration.

Patients may be reluctant to comply with their treatment regime, ascompliance may be painful and traumatic. For example, today there existtherapeutic agents that can treat, with good clinical success,ophthalmic conditions, such as age-related macular degeneration,diabetic macular edema, diabetic retinopathy, choroidalneovascularization, and other conditions that can lead to blindness ornear blindness. Often the afflicted population is an older patient groupwho must adjust their activities of daily living to cope with the earlystages of these diseases. However, as the disease progresses, permanenteye damage occurs and many clinically effective treatments are onlypreventative, and not restorative. Thus, consistent compliance to thetreatment regime is nearly mandatory to prevent loss of sight.

Unfortunately, treatment regimens typically require the patient to holdstill while the physician pierces the patient's eye with a hypodermicneedle to deliver the therapeutic agent into the eye, typically thevitreous of the eye. This can be traumatic and painful and accordingly apatient may be reluctant to receive the injections. The ability toprovide a longer-term benefit for each injection, and thus reduce thepain and trauma suffered by the patient, turns on the requiredpharmacokinetics of the therapeutic agent and the delivery vehicle thatcarries and releases the agent.

Some known delivery vehicles have active ingredients that areincorporated into polymer and sol-gel systems by entrapment duringsynthesis of the matrix phase. Microencapsulation techniques forbiodegradable polymers include such methods as film casting, molding,spray drying, extrusion, melt dispersion, interfacial deposition, phaseseparation by emulsification and solvent evaporation, air suspensioncoating, pan coating and in-situ polymerization. Melt dispersiontechniques are described, for example, in U.S. Pat. No. 5,807,574 andU.S. Pat. No. 5,665,428.

In an alternative approach, the active ingredient is loaded afterformation of the porous matrix is complete. Such carrier systemsgenerally have micron-sized rather than nanometer-sized pores to allowthe agents to enter into the pores. U.S. Pat. No. 6,238,705, forexample, describes the loading of macroporous polymer compositions bysimple soaking in a solution of the active ingredient and U.S. Pat. Nos.5,665,114 and 6,521,284 disclose the use of pressure to load the poresof implantable prostheses made of polytetrafluoroethene (PTFE). Whilethis approach may be effective for small organic molecules, largermolecules such as proteins tend to aggregate in large pores and do noteffectively release in vivo in a controlled manner.

With smaller pores, it has proved difficult to incorporate highconcentrations of therapeutic agents due to blocking of the narrowpores. Deposition of material towards the opening of the pores tends toprevent a high proportion of the material from occupying the poresystem. The problem of achieving high loading of the active ingredientlimits the effectiveness of many currently known delivery systems.

Another concern when delivering therapeutic agents through an deliveryvehicle is the biocompatibility of the delivery vehicle followingrelease of the drug. Bioerodible or resorbable delivery vehiclematerials would be an attractive alternative to delivery vehicles thatrequire removal following release of the drug. The design andpreparation of bioerodable delivery vehicles for carrying therapeuticagents has begun to be explored. PCT Publication No. WO2009/009563describes a drug delivery system comprising a porous silicon material.

Therefore, there remains a continuing need for the development ofimproved dosage forms for the controlled release of therapeutic agents,which are biocompatible and are capable of delivering large molecules ina sustained fashion.

SUMMARY

The invention comprises a composition comprising a bioerodible poroussilicon-based carrier material wherein the carrier material carries atleast one large molecule therapeutic agent and at least one amorphoussugar, optionally further comprising a crystallization inhibitor. Incertain embodiments, the composition is prepared using vacuum-assistedflash drying.

The disclosed compositions are for delivering therapeutic agents,particularly large molecules such as proteins, peptides, antibodies,carbohydrates, polymers, vaccines, small interfering RNA (siRNA) orpolynucleotides, in a controlled manner. The compositions comprise aporous silicon-based carrier material loaded with the therapeutic agentand an amorphous sugar. In some embodiments, the compositions comprise aporous silicon-based carrier material loaded with the therapeutic agentand a mixture of amorphous sugars. In some embodiments, the compositionscomprise a porous silicon-based carrier material loaded with thetherapeutic agent, and a mixture of a sugar and a crystallizationinhibitor. The compositions may be used in vitro or in vivo to deliverthe therapeutic agent, preferably in a controlled fashion over anintended period of time such as over multiple days, weeks or months. Thecarrier material is preferably formed from a bioerodible or resorbablematerial, e.g., a silicon-based material such as elemental silicon orsilicon dioxide, such that removal following release of the therapeuticagent is unnecessary. In certain such embodiments, the carrier materialand its breakdown products are biocompatible such that the biologicalside-effects from the bioerosion of the carrier material are minimal orinnocuous.

In certain embodiments, the carrier material comprises porous silicondioxide, such as mesoporous silicon dioxide. The average pore size ofthe carrier material is typically selected so that it may carry thetherapeutic agent, and example pore sizes are from 2-50 nm in diameter,such as from about 15 to about 40 nm in diameter, from about 20 to about30 nm in diameter, from about 2 to about 15 nm in diameter, or about 5to about 10 nm in diameter. Silicon-based materials are also disclosedin U.S. 20120177695, which is incorporated herein by reference.

In certain embodiments, the therapeutic agent is a protein with amolecular weight between about 500 amu and about 200,000 amu, and maybeabout 800 amu and about 200,000 amu, about 1000 amu and about 200,000amu, about 1500 amu and about 200,000 amu, about 2,000 amu and about200,000, about 5,000 amu and about 200,000 amu, about about 10,000 toabout 150,000 amu, between about 10,000 and about 50,000 amu, betweenabout 50,000 and about 100,000 amu or between about 100,000 and about200,000 amu.

The size of a therapeutic agent may alternatively be characterized bythe molecular radius, which may be determined, for example, throughX-ray crystallographic analysis or by hydrodynamic radius. Thetherapeutic agent may be a protein, e.g., with a molecular radiusselected from 0.5 nm to 20 nm, such as about 0.5 nm to 10 nm, even fromabout 1 to 8 nm. Preferably, a suitable pore radius to allow access toparticular agents, e.g., proteins, is selected according to apore-therapeutic agent (agent) differential, defined herein as thedifference between the radius of a agent and a radius of a pore. Forexample, the pore-agent differential for insulin, with a hydrodynamicradius of 1.3 nm and a pore with a minimum radius of 4.8 nm has apore-protein differential of 3.5 nm. A pore-agent differential may beused to determine minimum suitable average pore size for accommodating aprotein of a particular radius. The pore-protein differential maytypically be selected from about 3.0 to about 5.0 nm.

Typically the compositions are selected to have an average pore size toaccommodate the therapeutic agent. The average pore size of the carriermaterial may be chosen based on the molecular weight or the molecularradius of the therapeutic agent to be loaded into the pores of thecarrier material. For example, a therapeutic agent of molecular weightselected from 100,000 to 200,000 amu may be used with a carrier materialof larger average pore size such as from about 15 nm to about 40 nm. Incertain embodiments, a therapeutic agent of molecular weight selectedfrom 5,000 to 50,000 amu may be used with a carrier material of smalleraverage pore size such as from about 2 nm to about 10 nm.

In certain embodiments, the sugars, whether used alone or incombination, are selected from sucrose, fructose, glucose, erythritol,maltitol, lactitol, sorbitol, mannitol, xylitol, D-tagatose, trehalose,trehalose dehydrate, galactose, glycerol, rhamnose, cyclodextrin,raffinose, ribulose, ribose, threose, arabinose, xylose, lyxose, allose,altrose, mannose, idose, lactose, maltose, invert sugar, isotrehalose,neotrehalose, palatinose or isomaltulose, erythrose, deoxyribose,gulose, idose, talose, erythrulose, xylulose, psicose, turanose,cellobiose, glucosamine, mannosamine, fucose, glucuronic acid, gluconicacid, glucono-lactone, abequose, galactosamine, xylo-oligosaccharides,gentio-oligoscaccharides, galacto-oligosaccharides, sorbose,nigero-oligosaccharides, fructooligosaccharides, maltotetraol,maltotriol, maltodextrin, malto-oligosaccharides, lactulose, melibiose,or any combinations thereof. In preferred embodiments, the sugar isselected from trehalose, trehalose dihydrate, sucrose, mannitol,sorbitol, xylitol or glycerol, or a combination thereof.

In certain embodiments, the compositions are prepared by forming theporous carrier material first and then loading the pores with thetherapeutic agent, and the amorphous or solution form of the sugar, or aplurality of sugars, or a combination of a sugar and a crystallizationinhibitor. In preferred embodiments, the therapeutic agent is loadedbefore the amorphous or solution form of the sugar or thecrystallization inhibitor.

The invention includes methods for loading a therapeutic agent into thepore of a porous silicon-based carrier material, comprising contacting aporous silicon-based carrier material with a therapeutic agent. Oneexemplary method for loading a therapeutic agent into the pore of aporous silicon-based carrier material comprises selecting a poroussilicon-based carrier having pore sizes dimensionally adapted to allow asingle protein to load into the pore such that opposite sides of theprotein engage opposite sides of the pore. One method for loading atherapeutic agent into the pore of a porous silicon-based carriermaterial comprises selecting a porous silicon-based carrier having poresizes dimensionally adapted to admit only a single agent into the widthof a single pore at one time (i.e., longitudinal series along the lengthof a pore are not excluded), e.g., two agents could not be accommodatedif positioned side-by-side (laterally) within a pore. Methods forloading an agent into the pore of a silicon-based material and forselecting appropriate carrier materials for an agent of interest arealso disclosed in U.S. 20120177695, which is incorporated herein byreference.

The compositions may be disposed on the skin or on the surface of theeye. Alternatively, the compositions may be disposed within the body ofa mammal, such as within the eye of a patient, or within any othertissue or organ of the patient's body. In particular applications, thecompositions are disposed subcutaneously, subconjunctivally or in thevitreous of the eye. The compositions may be used for treating orpreventing conditions of a patient such as chronic diseases. In certainembodiments, the compositions are for treating or preventing diseases ofthe eye such as glaucoma, macular degeneration, diabetic macular edemaand age-related macular degeneration. The therapeutic agent may bereleased in a controlled manner over a period of weeks or months, forexample, to treat or prevent diseases of the eye such as maculardegeneration.

The invention comprises stabilized formulations comprising amorphoussugars and methods of stabilizing therapeutic agents in a porous carriermaterial as described herein. In certain embodiments, the inventioncomprises stabilized biomolecules, such as antibodies, in the pores ofthe carrier material such that the half-life or the shelf life of thebiomolecule is superior to the half-life or shelf life of thebiomolecule outside of the carrier material. In certain embodiments, theproteins of the stabilized formulations are stable to drying underreduced pressure at room temperature ambient conditions. In certainembodiments, the porous carrier material comprising a therapeutic agentand an amorphous sugar is coated with a polymer. In preferredembodiments, the porous carrier material comprising a therapeutic agentand an amorphous sugar is coated with a controlled release polymer.

In certain embodiments of compositions as described herein, theamorphous forms of sugars of the compositions described herein, when incontact with the porous carrier materials described herein, retain theiramorphous character at 25° C./60% relative humidity after 90 days thanunder similar conditions without the porous carrier materials. Incertain embodiments, the amorphous sugars stabilize biomolecules, e.g.,antibodies, at the temperature of 25° C. for at least 15 days, at least1 month, at least 6 months, at least 1 year, at least 1.5 years, atleast 2 years, at least 2.5 years, at least 3 years or at least 4 years.

In some embodiments, the stabilized formulations of the invention arestable when exposed to non-aqueous solvent such as dichloromethane, orany solvent not capable of solubilizing the sugar.

DETAILED DESCRIPTION

FIG. 1 shows the stabilisation of the amorphous sugars in mesoporousoxidized anodized silicon (e.g., as prepared by Examples 1-3) for 90days at 25° C. and 60% relative humidity.

FIG. 2 shows the stability of bevacizumab after vacuum drying onmesoporous oxidized anodized silicon versus commercial freeze drying.

FIG. 3 shows the dissolution of myoglobin co-formulated with sucrose incoated 60 Å mesoporous oxidized anodized silicon particles.

OVERVIEW

Sustained and controlled delivery of therapeutic agents to patients,particularly patients with chronic conditions such as glaucoma orcancer, is becoming increasingly important in modern medical therapy.Many therapies are most effective when administered at frequentintervals to maintain a near constant presence of the active agentwithin the body. While frequent administration may be recommended, theinconvenience and associated difficulty of patient compliance mayeffectively prevent treatment in this manner. As a result, sustainedrelease compositions that release therapeutic agents in a controlledmanner are very attractive in fields such as cancer therapy andtreatment of other chronic diseases.

Compositions that release therapeutic agents in vivo or in vitro may beformed from a variety of biocompatible or at least substantiallybiocompatible materials. One type of composition employs a silicon-basedcarrier material. Silicon-based carrier materials may include, forexample, elemental silicon, and oxidized silicon in forms such assilicon dioxide (silica), or silicates. Some silicon-based compositionshave demonstrated high biocompatibility and beneficial degradation inbiological systems, eliminating the need to remove the carrier materialfollowing release of the therapeutic agent.

Tests show that high porosity silicon-based materials, e.g., 80%porosity, are resorbed faster than medium porosity silicon-basedmaterial, e.g., 50% porosity, which in turn is resorbed faster than bulksilicon-based material, which shows little to no sign of bioerosion orresorption in biological systems. Furthermore, it is understood that theaverage pore size of the carrier material will affect the rate ofresorption. By adjusting the average pore size of a carrier material aswell as the porosity of the material, the rate of bioerosion may betuned and selected.

Silicon-based carrier materials are often prepared using hightemperatures and organic solvents or acidic media to form the porousmaterial and load the therapeutic agent within the pores. Theseconditions may be suitable for certain molecules such as salts,elements, and certain highly stable small organic molecules. However,for loading large organic molecules such as proteins or antibodies,caustic and/or severe conditions during the preparation or loading ofthe template could lead to denaturing and deactivation, if not completedegradation of the active agent. Loading large molecules such asantibodies into the carrier material under mild conditions is a featureof the methods described herein that is particularly advantageous forlarge organic molecules such as proteins.

The particle size of the silicon-based carrier material may also affectthe rate in which the pores of the carrier material may be loaded withthe therapeutic agent. Smaller particles, e.g., particles in which thelargest diameter is 20 microns or less, may load more rapidly thanparticles in which the largest diameter is greater than 20 microns. Thisis particularly apparent when the pore diameters are similar indimensions to the molecular diameters or size of the therapeutic agents.The rapid loading of smaller particles may be attributed to the shorteraverage pore depth that the therapeutic agent must penetrate in smallerparticles.

DEFINITIONS

As used herein the specification, “a” or “an” may mean one or more. Asused herein in the claim(s), when used in conjunction with the word“comprising”, the words “a” or “an” may mean one or more than one. Asused herein “another” may mean at least a second or more.

The terms “antibody” and “antibodies” broadly encompass naturallyoccurring forms of antibodies and recombinant antibodies, such assingle-chain antibodies, camelized antibodies, chimeric, and humanizedantibodies and multi-specific antibodies as well as fragments andderivatives of all of the foregoing, preferably fragments andderivatives having at least an antigenic binding site. Antibodyderivatives may comprise a protein or chemical moiety conjugated to theantibody. The term “antibody” is used in the broadest sense and coversfully assembled antibodies, and recombinant peptides comprising them.

“Antibody fragments” comprise a portion of an intact antibody,preferably the antigen-binding or variable region of the intactantibody. Examples of antibody fragments include Fab, Fab′, F(ab′)2, andFv fragments; diabodies; linear antibodies (Zapata et al. (1995) ProteinEng. 8(10):1057-1062); single-chain antibody molecules; andmultispecific antibodies formed from antibody fragments. Papaindigestion of antibodies produces two identical antigen-bindingfragments, called “Fab” fragments, each with a single antigen-bindingsite, and a residual “Fc” fragment, whose name reflects its ability tocrystallize readily. Pepsin treatment yields an F(ab′)2 fragment thathas two antigen-combining sites and is still capable of cross-linkingantigen.

Bioerode or bioerosion, as used herein, refers to the gradualdisintegration or breakdown of a structure or enclosure over a period oftime in a biological system, e.g., by one or more physical or chemicaldegradative processes, for example, enzymatic action, hydrolysis, ionexchange, or dissolution by solubilization, emulsion formation, ormicelle formation.

The term “preventing” is art-recognized, and when used in relation to acondition, such as a local recurrence (e.g., pain), a disease such ascancer, a syndrome complex such as heart failure or any other medicalcondition, is well understood in the art, and includes administration ofa composition which reduces the frequency of, or delays the onset of,symptoms of a medical condition in a subject relative to a subject whichdoes not receive the composition. Thus, prevention of cancer includes,for example, reducing the number of detectable cancerous growths in apopulation of patients receiving a prophylactic treatment relative to anuntreated control population, and/or delaying the appearance ofdetectable cancerous growths in a treated population versus an untreatedcontrol population, e.g., by a statistically and/or clinicallysignificant amount. Prevention of an infection includes, for example,reducing the number of diagnoses of the infection in a treatedpopulation versus an untreated control population, and/or delaying theonset of symptoms of the infection in a treated population versus anuntreated control population. Prevention of pain includes, for example,reducing the magnitude of, or alternatively delaying, pain sensationsexperienced by subjects in a treated population versus an untreatedcontrol population.

The term “prophylactic or therapeutic” treatment is art-recognized andincludes administration to the host of one or more of the subjectcompositions. If it is administered prior to clinical manifestation ofthe unwanted condition (e.g., disease or other unwanted state of thehost animal) then the treatment is prophylactic, (i.e., it protects thehost against developing the unwanted condition), whereas if it isadministered after manifestation of the unwanted condition, thetreatment is therapeutic, (i.e., it is intended to diminish, ameliorate,or stabilize the existing unwanted condition or side effects thereof).

Resorption or resorbing as used herein refers to the erosion of amaterial when introduced into or onto a physiological organ, tissue, orfluid of a living human or animal.

A “therapeutically effective amount” of a compound with respect to thesubject method of treatment refers to an amount of the compound(s) in apreparation which, when administered as part of a desired dosage regimen(to a mammal, preferably a human) alleviates a symptom, ameliorates acondition, or slows the onset of disease conditions according toclinically acceptable standards for the disorder or condition to betreated or the cosmetic purpose, e.g., at a reasonable benefit/riskratio applicable to any medical treatment.

As used herein, the term “treating” or “treatment” includes reversing,reducing, or arresting the symptoms, clinical signs, and underlyingpathology of a condition in manner to improve or stabilize a subject'scondition.

Unless otherwise indicated, the term large therapeutic molecule refersto molecules with molecular weights equal to or greater than 2000 amu,or even greater than 3000 amu.

Unless otherwise indicated, the term “small molecule” refers to anorganic molecule having a molecular weight less than about 2000 amu,preferably less than about 1500 amu, more preferably less than about1000 amu, or most preferably less than about 750 amu. Preferably, asmall molecule contains one or more heteroatoms.

Unless otherwise indicated, the term “sugar” refers to monosaccharides,disaccharides, oligosaccharides or sugar alcohols. Examples for the term“sugar” are, but not limited to, sucrose, fructose, glucose, erythritol,maltitol, lactitol, sorbitol, mannitol, xylitol, D-tagatose, trehalose,trehalose dehydrate, galactose, glycerol, rhamnose, cyclodextrin,raffinose, ribulose, ribose, threose, arabinose, xylose, lyxose, allose,altrose, mannose, idose, lactose, maltose, invert sugar, isotrehalose,neotrehalose, palatinose or isomaltulose, erythrose, deoxyribose,gulose, idose, talose, erythrulose, xylulose, psicose, turanose,cellobiose, glucosamine, mannosamine, fucose, glucuronic acid, gluconicacid, glucono-lactone, abequose, galactosamine, xylo-oligosaccharides,gentio-oligoscaccharides, galacto-oligosaccharides, sorbose,nigero-oligosaccharides, fructooligosaccharides, maltotetraol,maltotriol, maltodextrin, malto-oligosaccharides, lactulose, melibiose,or any combinations thereof.

Silicon-Based Carrier Materials

The devices and methods described herein provide, among other things,compositions comprising a porous silicon-based carrier material whereinat least one therapeutic agent and an amorphous sugar are disposed in apore of the carrier material. The described methods use suchcompositions for treatment or prevention of diseases, particularlychronic diseases. Furthermore, the described methods of preparingcompositions provide compositions which are characterized by sustainedand controlled release of therapeutic agents, particularly largemolecules such as proteins or antibodies.

The composition typically comprises a silicon-based carrier materialsuch as elemental silicon, silicon dioxide (silica), silicon monoxide,silicates (compounds containing a silicon-bearing anion, e.g., SiF₆ ²⁻,Si₂O₇ ⁶⁻, or SiO₄ ⁴⁻), or any combination of such materials. In certainembodiments, the carrier material comprises a complete or partialframework of elemental silicon and that framework is substantially orfully covered by a silicon dioxide surface layer. In other embodiments,the carrier material is entirely or substantially entirely silica.

In certain embodiments, the carrier material comprises silica, such asgreater than about 50% silica, greater than about 60 wt % silica,greater than about 70 wt % silica, greater than about 80 wt % silica,greater than about 90 wt % silica, greater than about 95 wt % silica,greater than 99 wt % silica, or even greater than 99.9 wt % silica.Porous silica may be purchased from suppliers such as Davisil,Salicycle, and Macherey-Nagel.

In certain embodiments, the carrier material comprises elementalsilicon, greater than 60 wt % silicon, greater than 70 wt % silicon,greater than 80 wt % silicon, greater than 90 wt % silicon, or evengreater than 95% silicon. Silicon may be purchased from suppliers suchas Vesta Ceramics.

Purity of the silicon-based material can be quantitatively assessedusing techniques such as Energy Dispersive X-ray Analysis, X-rayfluorescence, Inductively Coupled Optical Emission Spectroscopy or GlowDischarge Mass Spectroscopy.

The carrier material may comprise other components such as metals,salts, minerals or polymers. The carrier material may have a coating(such as a polymer coating) disposed on at least a portion of thesurface, e.g., to improve biocompatibility of the carrier materialand/or affect release kinetics.

The silicon-based carrier material may comprise elemental silicon orcompounds thereof, e.g., silicon dioxide or silicates, in an amorphousform. In some embodiments, the silicon-based carrier material comprisesfumed silica. In certain embodiments, the elemental silicon or compoundsthereof is present in a crystalline form. In other embodiments, thecarrier material comprises amorphous silica and/or amorphous silicon. Incertain embodiments, the silicon-based material is greater than about 60wt % amorphous, greater than about 70 wt % amorphous, greater than about80 wt % amorphous, greater than about 90 wt % amorphous, greater thanabout 92 wt % amorphous, greater than about 95 wt % amorphous, greaterthan about 99 wt % amorphous, or even greater than 99.9 wt % amorphous.

X-ray diffraction analysis can be used to identify crystalline phases ofsilicon-based material. Powder diffraction can be taken, for example, ona Scintag PAD-X diffractometer, e.g., equipped with a liquid nitrogencooled germanium solid state detector using Cu K-alpha radiation.

The silicon-based material may have a porosity of about 40% to about 95%such as about 60% to about 80%. Porosity, as used herein, is a measureof the void spaces in a material, and is a fraction of the volume ofvoids over the total volume of the material. In certain embodiments, thecarrier material has a porosity of at least about 10%, at least about20%, at least about 30%, at least about 40%, at least about 50%, atleast about 60%, at least about 70%, at least about 80%, or even atleast about 90%. In particular embodiments, the porosity is greater thanabout 40%, such as greater than about 50%, greater than about 60%, oreven greater than about 70%.

The carrier material of the compositions may have a surface area toweight ratio selected from about 20 m²/g to about 2000 m²/g, such asfrom about 20 m²/g to about 1000 m²/g, or even from about 100 m²/g toabout 300 m²/g. In certain embodiments, the surface area is greater thanabout 200 m²/g, greater than about 250 m²/g or greater than about 300m²/g.

In certain embodiments, the therapeutic agent is distributed to a poredepth from the surface of the carrier material of at least about 10microns, at least about 20 microns, at least about 30 microns, at leastabout 40 microns, at least about 50 microns, at least about 60 microns,at least about 70 microns, at least about 80 microns, at least about 90microns, at least about 100 microns, at least about 110 microns, atleast about 120 microns, at least about 130 microns, at least about 140microns or at least about 150 microns. In certain embodiments, thetherapeutic agent is distributed in the pores of the carrier materialsubstantially uniformly.

The therapeutic agent may be loaded into the carrier material to a depthwhich is measured as a ratio to the total width of the carrier material.In certain embodiments, the therapeutic agent is distributed to a depthof at least about 10% into the carrier material, to at least about 20%into the carrier material, at least about 30% into the carrier material,at least about 40% into the carrier material, at least about 50% intothe carrier material, or at least about 60% into the carrier material.

The amorphous sugar may be loaded into the carrier material to a depthwhich is measured as a ratio to the total width of the carrier material.In certain embodiments, the amorphous sugar is distributed to a depth ofat least about 1% to at least about 9%, to at least 10% into the carriermaterial, to at least about 20% into the carrier material, at leastabout 30% into the carrier material, at least about 40% into the carriermaterial, at least about 50% into the carrier material, or at leastabout 60% into the carrier material. In some embodiments, the amorphoussugar may seal the pores.

The amorphous sugar may be loaded into the carrier material to a weightthat is measured as a ratio to the combined weight of the carriermaterial and therapeutic agent. In certain embodiments, the amorphoussugar is loaded to a weight at least about 1% to at least about 80%, atleast about 1% to at least about 70%, at least about 1% to at leastabout 60%, at least about 1% to at least about 50%, at least about 1% toat least about 40%, at least about 1% to at least about 30%, at leastabout 1% to at least about 20%, to at least about 1% to at least about15%, about 1% to at least about 10%, about 1% to at least about 5%,about 1% to at least about 4%, at least about 1% to at least about 3%,or at least about 1% to at least about 2%. In certain embodiments, theamorphous sugar is loaded to a weight at least about 5% to at leastabout 10%, at least about 10% to at least about 20%, at least about 10%to at least about 30%, at least about 30% to at least about 40%, atleast about 40% to at least about 50%, at least about 50% to at leastabout 60%, at least about 60% to at least about 70%, or at least about70% to at least about 80%. In certain embodiments, the amorphous sugarmay be loaded to a weight of about 30%. Quantification of gross loadingmay be achieved by a number of analytic methods, for example,gravimetric, EDX (energy-dispersive analysis by x-rays), Fouriertransform infra-red (FTIR) or Raman spectroscopy of the pharmaceuticalcomposition or by UV spectrophotometry, titrimetric analysis, HPLC ormass spectroscopy of the eluted therapeutic agent in solution.Quantification of the uniformity of loading may be obtained bycompositional techniques that are capable of spatial resolution such ascross-sectional EDX, Auger depth profiling, micro-Raman and micro-FTIR.

Porous silicon-based materials of the invention may be categorized bythe average diameter of the pore size. Microporous silicon-basedmaterial has an average pore size less than 2 nm, mesoporoussilicon-based material has an average pore size of between 2-50 nm andmacroporous silicon-based material has a pore size of greater than 50nm. In certain embodiments, greater than 50% of the pores of thesilicon-based material have a pore size from 2-50 nm, greater than 60%of the pores of the silicon-based material have a pore size from 2-50nm, greater than 70% of the pores of the silicon-based material have apore size from 2-50 nm, greater than 80% of the pores of thesilicon-based material have a pore size from 2-50 nm, or even greaterthan 90% of the pores of the silicon-based material have a pore sizefrom 2-50 nm.

In certain embodiments, the carrier material comprises porous silicondioxide, such as mesoporous silicon dioxide. In certain embodiments, theaverage pore size of the carrier material is selected from 2-50 nm, suchas from about 15 to about 40 nm, such as about 20 to about 30 nm. Incertain embodiments, the average pore size is selected from about 2 toabout 15 nm, such as about 5 to about 10 nm. In certain embodiments, theaverage pore size is about 30 nm.

The pore size may be preselected to the dimensional characteristics ofthe therapeutic agent to control the release rate of the therapeuticagent in a biological system. Typically, pore sizes that are too smallpreclude loading of the therapeutic agent, while oversized pores do notinteract with the therapeutic agent sufficiently strongly to control therate of release. For example, the average pore diameter for a carriermaterial may be selected from larger pores, e.g., 15 nm to 40 nm, forhigh molecular weight molecules, e.g., 200,000-500,000 amu, and smallerpores, e.g., 2 nm to 10 nm, for molecules of a lower molecular weight,e.g., 10,000-50,0000 amu. For instance, average pore sizes of about 6 nmin diameter may be suitable for molecules of molecular weight around14,000 to 15,000 amu such as about 14,700 amu. Average pore sizes ofabout 10 nm in diameter may be selected for molecules of molecularweight around 45,000 to 50,000 amu such as about 48,000 amu. Averagepore sizes of about 25-30 nm in diameter may be selected for moleculesof molecular weight around 150,000 nm.

The pore size may be preselected to be adapted to the molecular radii ofthe therapeutic agent to control the release rate of the therapeuticagent in a biological system. For instance, average pore sizes of about25 nm to about 40 nm in diameter may be suitable for molecules with alargest molecular radius from about 6 nm to about 8 nm. Molecular radiimay be calculated by any suitable method such as by using the physicaldimensions of the molecule based on the X-ray crystallography data orusing the hydrodynamic radius which represents the solution state sizeof the molecule. As the solution state calculation is dependant upon thenature of the solution in which the calculation is made, it may bepreferable for some measurements to use the physical dimensions of themolecule based on the X-ray crystallography data. As used herein thelargest molecular radius reflects half of the largest dimension of thetherapeutic agent.

In certain embodiments, the average pore diameter is selected to limitthe aggregation of molecules, e.g., proteins, within a pore. It would beadvantageous to prevent biomolecules such as proteins from aggregatingin a carrier material as this is believed to impede the controlledrelease of molecules into a biological system. Therefore, a pore that,due to the relationship between its size and the size of a biomolecule,allows, for example, only one biomolecule to enter the pore at any onetime, will be preferable to a pore that allows multiple biomolecules toenter the pore together and aggregate within the pore. In certainembodiments, multiple biomolecules may be loaded into a pore, but due tothe depth of the pore, the proteins distributed throughout this depth ofthe pore will aggregate to a lesser extent.

In certain embodiments, the therapeutic agent is selected from any agentuseful in the treatment or prevention of diseases. In certainembodiments, the agent is selected from small molecule therapeuticagents, i.e., compounds with molecular weights less than 1000 amu. Inpreferred embodiments, the therapeutic agents are selected from largemolecules with molecular weight equal to or greater than 1000 amu. Incertain embodiments, the therapeutic agent of the invention is abiomolecule. Biomolecules, as used herein, refer to any molecule that isproduced by a living organism, including large polymeric molecules suchas proteins, polysaccharides, and nucleic acids as well as smallmolecules such as primary metabolites, secondary metabolites, andnatural products or synthetic variations thereof. In particular,proteins such as antibodies, ligands, and enzymes may be used astherapeutic agents of the invention. In particular embodiments, thebiomolecules of the invention have molecular weights ranging from about10,000 amu to about 500,000 amu. In certain embodiments, the therapeuticagent is selected from one or more monoclonal antibodies, such asranibizumab (Lucentis) and bevacizumab (Avastin).

In certain embodiments, the therapeutic agent has a molecular weightbetween 10,000 and 50,000 amu, between 50,000 and 100,000 amu or between100,000 and 150,000 amu. In certain embodiments, the therapeutic agentis a protein with a molecular weight between 5,000 amu and 200,000 amu,such as about 10,000 to about 150,000 amu.

The size of a therapeutic agent may alternatively be characterized bythe molecular radius, which may be determined, for example, throughX-ray crystallographic analysis or by hydrodynamic radius. Thetherapeutic agent may be a protein, e.g., with a molecular radiusselected from 0.5 nm to 20 nm such as about 0.5 nm to 10 nm, even fromabout 1 to 8 nm.

A therapeutic agent with molecular radius from 1 to 2.5 nm may beadvantageously used with a carrier material with a minimum pore radiusof from 4.5 to 5.8 nm. A therapeutic agent with a molecular radius of 7nm may be advantageously used with a carrier material with a minimumpore radius of from 11 to 13 nm, such as about 12 nm. For example,insulin with a hydrodynamic radius of 1.3 nm may be used with a carriermaterial that has an average minimum pore radius of 4.8 nm.

The protein-pore differential may be used to choose a suitable carriermaterial to accommodate the therapeutic agent. This calculationsubtracts the molecular radius from the pore radius. Typically, theradius of the therapeutic agent would be the hydrodynamic radius orlargest radius determined through x-ray crystallographic analysis. Thepore radius would typically be the average pore radius of the carriermaterial. For example, the pore-protein differential for insulin, with ahydrodynamic radius of 1.3 nm and a pore with a minimum radius of 4.8 nmhas a protein-pore differential of 3.5 nm. In certain embodiments, theprotein-pore differential is selected from 3 to 6 nm, such as from 3.2to 4.5 nm. The protein-pore differential may be about 3.2 nm, about 3.3nm, about 3.4 nm, about 3.5 nm, about 3.6 nm, about 3.7 nm, about 3.8nm, about 3.9 nm, about 4.0 nm, about 4.1 nm, about 4.2 nm, about 4.3nm, about 4.4 nm or about 4.5 nm.

In certain embodiments, the therapeutic agent is an antibody and theaverage pore size of the carrier material is selected from about 20 nmto about 40 nm such as from about 25 nm to 35 nm such as about 30 nm. Incertain embodiments, the therapeutic agent is an antibody selected frombevacizumab or ranibizumab and the average pore size of the carriermaterial is selected from about 20 nm to about 40 nm such as from about25 nm to 35 nm such as about 30 nm. In certain embodiments, thetherapeutic agent is bevacizumab and the average pore size of thecarrier material is about 30 nm.

In certain embodiments, the walls of the carrier material that separatethe pores have an average width of less than 5 nm, such as about 4.8 nm,about 4.6 nm, about 4.4 nm, about 4.2 nm, about 4.0 nm, about 3.8 nm,about 3.6 nm, about 3.4 nm, about 3.2 nm, about 3.0 nm, about 2.8 nm, oreven about 2.6 nm. In certain embodiments, the walls of the carriermaterial that separate the pores have an average width of less thanabout 3 nm, such as about 2.8 nm, about 2.6 nm, about 2.4 nm, about 2.2nm, about 2.0 nm, about 1.8 nm, about 1.6 nm, about 1.4 nm, about 1.2nm, about 1.0 nm, or even about 0.8 nm.

Dimensionality and morphology of the carrier material can be measured,for example, by Transmission Electron Microscopy (TEM) using a 2000 JEOLelectron microscope operating, for example, at 200 keV. Samples for TEMcan be prepared by dispensing a large number of porous carrier materialparticles onto a holey carbon film on a metal grid, via a dilute slurry.

In certain embodiments, the pores of the carrier material define spacehaving a volume of about 0.1 mL/g to about 5 mL/g of the carriermaterial. In certain embodiments, the pore volume is about 0.2 mL/g toabout 3 mL/g, such as about 0.4 mL/g to about 2.5 mL/g, such as about1.0 mL/g to about 2.5 mL/g.

In certain embodiments, the load level of the carrier material is up to80% by weight based on the combined weight of the carrier material andthe therapeutic agent. The load level is calculated by dividing theweight of the loaded therapeutic agent by the combined weight of theloaded therapeutic agent and carrier material and multiplying by 100. Incertain embodiments, the load level of the carrier material is greaterthan 1%, such as greater than 3%, such as greater than 5%, such asgreater than 10%, such as greater than 15%, greater than 20%, greaterthan 25%, greater than 30%, greater than 35%, greater than 40%, greaterthan 45%, such as greater than 50%, such as greater than 60%, or greaterthan 70%. The load level may be between about 5% and about 10%. Incertain embodiments, the load level of the carrier material is betweenabout 10% and about 20%, between about 20% and about 30%, between about30% and about 40%, between about 40% and about 50%, between about 50%and about 60%, between about 60% and about 70% or between about 70% andabout 80% by weight.

In certain embodiments, the load level of the carrier material is up to40% weight based on the weight of the composition. In certainembodiments, the load level of the carrier material is greater than 1%,such as greater than 3%, such as greater than 5%, such as greater than10%, such as greater than 15%, greater than 20%, greater than 25%,greater than 30%, or greater than 35%. The load level may be betweenabout 5% and about 10%. In certain embodiments, the load level of thecarrier material is between about 10% and about 20%, between about 20%and about 30%, between about 30% and about 40% by weight. The load levelis calculated by dividing the weight of the loaded therapeutic agentdivided by the weight of the composition and multiplying by 100. Thecomposition may comprise the carrier material, the therapeutic agent,the amorphous sugar and optionally other components such as acrystallization inhibitor. In some embodiments, the compositioncomprises:

a therapeutic agent (such as a protein) in the range of 1% to 40% byweight,an amorphous sugar in the range of 1% to 50% by weight, anda carrier material in the range of 10% to 30% by weight.

The load volume of the carrier materials described herein may beevaluated in terms of the volume of the pores in the porous materialbeing occupied by the therapeutic agent. The percentage of the maximumloading capacity that is occupied by the therapeutic agent (that is, thepercentage of the total volume of the pores in the porous carriermaterial that is occupied by the therapeutic agent) for carriermaterials according to the invention may be from about 30% to about100%, such as from about 50% to about 90%. For any given carriermaterial, this value may be determined by dividing the volume of thetherapeutic agent taken up during loading by the void volume of thecarrier material prior to loading and multiplied by one hundred.

In certain embodiments, the carrier materials of the invention areparticles that, measured at the largest diameter, have an average sizeof about 1 to about 500 microns, such as about 5 to about 100 microns.In certain embodiments, a single carrier material particle measured atits largest diameter is about 1 to about 500 microns, such as about 5 toabout 500 microns.

In order to increase the rate of loading of the particles of theinvention, it may be advantageous to use relatively small particles. Assmaller particles have pores with less depth for the therapeutic agentto penetrate, the amount of time needed to load the particles may bereduced. This may be particularly advantageous when the pore diametersare similar in dimensions to the molecular diameters or size of thetherapeutic agents. Smaller particles may be from 1-20 microns, such asabout 10-20 microns, e.g., about 15-20 microns, measured at the largestdimension.

In some aspects, greater than 60%, greater than 70%, greater than 80% orgreater than 90% of the particles have a particle size of from 1-20microns, preferably 5-15 microns, measured at the largest dimension. Theparticles may have an average particle size between 1 and 20 micronssuch as between 5-15 microns or about 15 microns, about 16 microns,about 17 microns, about 18 microns, about 19 microns.

Particle size distribution, including the mean particle diameter can bemeasured, for example, using a Malvern Particle Size Analyzer, ModelMastersizer, from Malvern Instruments, UK. A helium-neon gas laser beammay be projected through an optical cell containing a suspension of thecarrier material. Light rays striking the carrier material are scatteredthrough angles which are inversely proportional to the particle size.The photodetector array measures the light intensity at severalpredetermined angles and electrical signals proportional to the measuredlight flux values are then processed by a microcomputer system against ascatter pattern predicted from the refractive indices of the samplecarrier material and aqueous dispersant.

Larger carrier material particles or implants are also envisioned forcontrolled delivery of therapeutic agents. The particles/implants of theinvention may have an average size of about 1 mm to about 5 cm measuredat the largest dimension. In certain embodiments, the particles/implantshave an average size of about 5 mm to about 3 cm measured at the largestdimension. Particles greater than 1 mm, as measured at the largestdimension, may be useful for intramuscular subcutaneous, intravitreal orsubdermal drug delivery.

In certain embodiments, the amorphous sugars described herein present inthe pores are used to stabilize sensitive therapeutic compounds, such asbiomolecules, e.g., antibodies. In certain embodiments, biomoleculesthat are partially or wholly unstable at elevated temperatures, such asroom temperature or above, can be made stable at room temperature forprolonged periods of time. For example, the biomolecule formulated withamorphous sugars within the carrier material is stable to drying underreduced pressure at room temperature.

In certain embodiments, the porous carrier materials described hereinare used to stabilize sensitive therapeutic compounds, such asbiomolecules, e.g., antibodies. In certain embodiments, biomoleculesthat are partially or wholly unstable at elevated temperatures, such asroom temperature or above, can be made stable at room temperature forprolonged periods of time. The biomolecules may be loaded into a carriermaterial such that an aqueous suspension of the biomolecule loaded intothe carrier material is more stable than a corresponding aqueoussolution of the biomolecule (i.e., an identical aqueous solution withand without the addition of the porous carrier material). For example,the biomolecule within the carrier material may have a half-life at roomtemperature (e.g., about 23° C.) that is greater than a half-life of thebiomolecule without the carrier material under the same conditions. Incertain embodiments, a biomolecule in the pores of the carrier materialhas a half-life that is at least twice as long as the biomoleculeoutside of the carrier material under the same conditions, morepreferably, at least five times, at least 10 times, at least than 15times, at least 20 times, at least 30 times, at least 40 times, at least50 times, at least 60 times, or at least 100 times as long as thebiomolecule outside of the carrier material. For example, an antibodywithin the pores of the carrier material may have a half-life that is atleast 10 times as long as the antibody outside of the carrier material,more preferably, at least 20 times as long.

Similarly, biomolecules formulated with amorphous sugars may have alonger shelf life within the pores of the carrier material than in acorresponding aqueous solution, preferably at least twice as long, atleast five times as long, at least 10 times as long, at least 20 timesas long, at least 30 times as long, at least 40 times as long, at least50 times as long, at least 60 times as long or at least 100 times aslong. For example, an antibody within the pores of the carrier materialmay have a longer shelf life than an antibody outside of the carriermaterial, preferably at 10 times as long, at least 20 times as long.

In certain embodiments, porous compositions comprising the carriermaterial and, a biomolecule, such as an antibody, and amorphous sugarsexhibit stability at the temperature of 25° C. for at least 15 days, oreven about 1 month. Additionally or alternatively, in certainembodiments, the antibody-loaded carrier materials are stable at 25° C.for at least 6 months, at least 1 year, at least 1.5 years, at least 2years, at least 2.5 years, at least 3 years or at least 4 years.Stability may be assessed, for example, by high performance sizeexclusion chromatography (HPSEC) or by comparing the biological activityof the stored biomolecule-loaded compositions against a sample offreshly prepared biomolecule-loaded compositions or against the activityof the compositions as measured prior to storage. Activity ofantibodies, for example, can be assessed by various immunological assaysincluding, for example, enzyme-linked immunosorbent assay (ELISA) andradioimmunoassay. Preferably, at the end of the storage period, theactivity of the stored compositions is at least 75%, at least 80%, atleast 85%, at least 90%, at least 95%, at least 98%, at least 99%, atleast 99.5%, at least 99.8%, or even at least 99.9% of the activity ofthe corresponding freshly prepared compositions. Accordingly, theinvention contemplates methods of treatment wherein biomolecule-loadedcompositions are stored at 25° C. for at least 6 months, at least 1year, at least 1.5 years, at least 2 years, at least 2.5 years, at least3 years or at least 4 years prior to administering the compositions to apatient.

The invention further comprises methods of stabilizing biomolecules.Methods of the invention comprise loading biomolecules into the pores ofthe carrier material through any suitable method to form thecompositions of the invention.

Methods of Preparation

The invention also provides methods of preparing silicon-based carriermaterials. In certain embodiments, porous silicon-based carrier materialmay be prepared synthetically. For example, porous silica may besynthesized by reacting tetraethyl orthosilicate with a template made ofmicellar rods. In certain embodiments, the result is a collection ofspheres or rods that are filled with a regular arrangement of pores. Thetemplate can then be removed, for example, by washing with a solventadjusted to the proper pH. In certain embodiments, the poroussilicon-based carrier material may be prepared using a sol-gel method ora spray drying method. In certain embodiments, the porous silicon basedcarrier material may be prepared by flame hydrolysis of silicontetrachloride in an oxy-hydrogen flame. In certain embodiments, thepreparation of the carrier material involves one or more techniquessuitable for preparing porous silicon-based material.

Pores may be introduced to the silicon-based carrier material throughtechniques such as anodization, stain etching, or electrochemicaletching. In an exemplary embodiment, anodization employs a platinumcathode and silicon wafer anode immersed in Hydrogen Fluoride (HF)electrolyte. Corrosion of the anode producing pores in the material isproduced by running electrical current through the cell. In particularembodiments, the running of constant DC is usually implemented to ensuresteady tip-concentration of HF resulting in a more homogeneous porositylayer.

In certain embodiments, pores are introduced to the silicon-basedcarrier material through stain-etching with hydrofluoric acid, nitricacid and water. In certain embodiments, a combination of one or morestain-etching reagents are used, such as hydrofluoric acid and nitricacid. In certain embodiments, a solution of hydrofluoric acid and nitricacid are used to form pores in the silicon-based material.

The porosity of the material can be determined by weight measurement.BET analysis may be used to determine any one or more of the porevolume, pore size, pore size distribution and surface area of thecarrier material. BET theory, named after the combined surname initialsof authors of the theory, applies to the physical adsorption of gasmolecules on a solid surface and serves as the basis for an importantanalysis technique for the measurement of the specific surface area of amaterial (J. Am. Chem. Soc. v. 60, p 309 (1938)). The BET analysis maybe performed, for example, with a Micromeritics ASAP 2000 instrumentavailable from Micromeritics Instrument Corporation, Norcross, Ga. In anexemplary procedure, the sample of carrier material may be outgassedunder vacuum at temperatures, for example, greater than 200° C. for aperiod of time such as about 2 hours or more before the measurements aretaken. In certain embodiments, the pore size distribution curve isderived from the analysis of the adsorption branch of the isothermoutput. The pore volume may be collected at the P/P0=0.985 single point.

One or more drying techniques may be used in the preparation of poroussilicon-based materials of the invention. For example, to preventcracking of the porous silicon-based material, the material may be driedby supercritical drying, freeze drying, pentane drying, slowevaporation, spray drying or vacuum-assisted flash drying. Supercriticaldrying involves superheating the liquid pore above the critical point toavoid interfacial tension. Freeze drying involves freezing and sublimingany solvents under vacuum. Pentane drying uses pentane as the dryingliquid instead of water and as a result may reduce capillary stress dueto the lower surface tension. Slow evaporating is a technique which canbe implemented following the water or ethanol rinsing and may beeffective at decreasing the trap density of solvent within the material.Spray drying is a technique whereby a solution of protein and sugar isspray dried so that the water is evaporated sufficiently quickly toallow the sugar to go from a solution to a solid without reordering intoa crystal. Vacuum-assisted flash drying is a technique whereby theporous matrix assists the rapid drying of the formulation under reducedpressure whilst stabilising the amorphous sugar. Vacuum-assisted flashdrying may be performed at room temperature, which is desirable forphysically stabilized amorphous systems such as biomolecules and sugars.

The surface of the porous silicon-based material may be modified toexhibit properties such as improved stability, cell adhesion orbiocompatibility. Optionally, the material may be exposed to oxidizingconditions such as through thermal oxidation. In an exemplaryembodiment, the process of thermal oxidation involves heating thesilicon-based material to a temperature above 1000° C. to promote fulloxidation of the silicon-based material. Alternatively, the surface ofthe carrier material may be oxidized so that the carrier materialcomprises a framework of elemental silicon partially, substantially orfully covered by an oxizided surface such as a silicon dioxide surface.

The surface of the porous silicon-based material or a portion thereofmay be derivatized. In an exemplary embodiment, the surface of a poroussilicon-based material may be derivatized with organic groups such asalkanes or alkenes. In a particular embodiment, the surface of thecarrier material may be derivatized by hydrosilation of silicon. Inparticular embodiments, the derivatized carrier materials may functionas biomaterials, incorporating into living tissue.

Any one or more of electrostatic interactions, capillary action andhydrophobic interactions may enable loading of the therapeutic agentinto the pores of the carrier material. In certain embodiments, thecarrier material and therapeutic molecules are placed in a solution andthe large molecules, e.g., proteins or other antibodies, are drawn fromthe solution into the pores of the carrier material, reminiscent of amolecular sieve's ability to draw water from an organic liquid.Hydrophobic drugs may be better suited for loading into carriermaterials that are predominantly formed from silicon (e.g., greater than50% of the material is silicon) while hydrophilic drugs may be bettersuited for loading into a carrier material that is characterized asmostly silica (e.g., greater than 50% of the carrier material issilica). In certain embodiments, the loading of large molecules into thepores of the carrier material is driven by external factors such assonication or heat. The carrier material may have an electrostaticcharge and/or the therapeutic agent may have an electrostatic charge.Preferably, the carrier material has the opposite electrostatic chargeas the therapeutic agent such that adsorption of the therapeutic agentinto the pores of the carrier material is facilitated by the attractiveelectrostatic forces. In certain embodiments, the therapeutic agent orthe carrier material itself does not have an electrostatic charge underneutral conditions, but is polarizable or ionizable. For example, insuch embodiments, the carrier material and/or the therapeutic agent maybe ionized to facilitate the adsorption of the therapeutic agent in thepores of the carrier material. For example, in the body, atphysiological pH, silicon dioxide exhibits a negatively charged surface,which promotes electrostatic adsorption of positively charged peptides.Similarly, molecules with carboxylic acids, phosphoric, and/or sulfonicacids are ionized with increasing pH to negatively charged carboxylate,phosphate, and/or sulfonate salts, while nitrogenated molecules (e.g.,bearing amine, guanidine, or other basic substituents) are protonatedwith decreasing pH to ammonium, guanidinium, or other positively chargedsalts.

The carrier material may comprise a coating or surface modification toattract the therapeutic agent into the pores. In certain embodiments,the carrier material is coated or modified in whole or in part with amaterial comprising moieties that are charged in order to attract aprotein or antibody into the pores of the carrier material. In otherembodiments, the moieties may be appended directly to the carriermaterial. For example, amine groups may be covalently appended onto thesurface of the carrier material such that when protonated atphysiological pH, the surface of the carrier material carries a positivecharge, thereby, for example, attracting a protein or antibody with anegatively charged surface. In other embodiments, the carrier materialmay be modified with carboxylic acid moieties such that whendeprotonated at physiological pH, the carrier material carries anegative charge, thereby attracting proteins or antibodies withpositively charged surfaces into the pores.

In certain embodiments, the therapeutic agent may be incorporated intothe carrier material following complete formation of the carriermaterial. Alternatively, the therapeutic agent may be incorporated intothe carrier material at one or more stages of preparation of the carriermaterial. For example, the therapeutic agent may be introduced to thecarrier material prior to a drying stage of the carrier material, orafter the drying of the carrier material or at both stages. In certainembodiments, the therapeutic agent may be introduced to the carriermaterial following a thermal oxidation step of the carrier material.

More than one therapeutic agent may be incorporated into a carriermaterial. In certain such embodiments, each therapeutic agent may beindividually selected from small organic molecules and large moleculessuch as proteins and antibodies. For example, an ocular carrier materialmay be impregnated with two therapeutic agents for the treatment ofglaucoma, or one therapeutic agent for the treatment of maculardegeneration and another agent for the treatment of glaucoma.

In certain aspects, e.g., when both small molecule therapeutic agentsand larger molecular therapeutic agents such as proteins areincorporated into a carrier material, the therapeutic agents may beincorporated into the carrier material at different stages of thepreparation of the composition. For example, a small molecule therapymay be introduced into the carrier material prior to an oxidation ordrying step and a large molecule therapeutic agent may be incorporatedfollowing an oxidation or drying step. Similarly, multiple differenttherapeutic agents of the same or different types may be introduced intoa finished carrier material in different orders or essentiallysimultaneously.

When a carrier material comprises a single material, or combination ofmultiple materials with multiple pore sizes, the larger therapeuticagent is preferably added to the carrier material prior to adding thesmaller therapeutic agent to avoid filling the larger pores with thesmaller therapeutic agent and interfering with adsorption of the largertherapeutic agent. For example, if a carrier material comprises a singlematerial, or combination of multiple materials, that has somewell-defined pores that are about 6 nm in diameter (i.e., suitable formolecules of molecular weight around 14,000 to 15,000 amu) and somewell-defined pores that are about 10 nm in diameter (i.e., suitable formolecules of molecular weight around 45,000 to 50,000 amu), the lattertherapeutic agent (i.e., the one with molecules of molecular weightaround 45,000 to 50,000 amu) are preferably added to the carriermaterial prior to adding the smaller therapeutic agent (i.e., the onewith molecules of molecular weight around 14,000 to 15,000 amu).Alternatively and additionally, in the embodiment wherein the twodifferent porous materials together comprise the device, each carriermaterial may be separately loaded with a different therapeutic agent andthen the carrier materials may be combined to yield the device.

The therapeutic agent may be introduced into the carrier material inadmixture or solution with one or more pharmaceutically acceptableexcipients. The therapeutic agent may be formulated for administrationin any suitable manner, typically in the form of a composition, suitablyfor subcutaneous, intramuscular, intraperitoneal or epidermalintroduction or for implantation into an organ (such as the liver, lungor kidney). Therapeutic agents according to the invention may beformulated for parenteral administration in the form of an injection,e.g., intraocularly, intravenously, intravascularly, subcutaneously,intramuscularly or infusion, or for oral administration.

The carrier material may be in any suitable form prior to loading withthe therapeutic agent such as in the form of a dry powder or particulateor formulated in an aqueous slurry, e.g., with a buffer solution orother pharmaceutically acceptable liquid. The therapeutic agent may bein any suitable form prior to loading into the carrier material such asin a solution, slurry, or solid such as a lyophilisate. The carriermaterial and/or the therapeutic agent may be formulated with othercomponents such as excipients, preservatives, stabilizers, e.g., sugars,or therapeutic agents, e.g., antibiotic agents.

The therapeutic agent may be formulated (and packaged and/ordistributed) as a solution with a concentration of >50 mg/mL, suchas >60 mg/mL, such as >75 mg/mL. In an exemplary embodiment, thetherapeutic agent is becacizumab and the becacizumab may be formulatedwith a concentration of >50 mg/mL, such as >60 mg/mL, such as >75 mg/mLin, for example, a phosphate buffer solution. The therapeutic agent maybe formulated (and packaged and/or distributed) with a surfactant and/ora stabilizer, e.g., sugars, wherein the therapeutic agent has a maximumconcentration of 50 mg/mL. A protein fragment, such as an antibodyfragment, may be formulated (and packaged and/or distributed) as asolution with a concentration of >10 mg/mL, >15 mg/mL or >20 mg/mL.

The therapeutic agent may be formulated (and packaged and/ordistributed) with stabilizers, excipients, surfactants or preservatives.In some embodiments, the stabilizers, excipients, surfactants orpreservatives are sugars. In particular embodiments, the sugars areselected from thehalose, sucrose, mannitol, sorbitol, xylitol orglycerol. In other embodiments, the therapeutic agent is formulated (andpackaged and/or distributed) essentially free of any one or more ofstabilizers, excipients, surfactants and preservatives, e.g., containsless than 1 mg/mL or preferably less than 0.1 mg/mL of a stabilizer,excipients, surfactant or preservative. The formulation of thetherapeutic agent may contain less than 1 mg/mL of surfactants such asless than 0.1 mg/mL of surfactants.

In certain embodiments, the composition may comprise a coatingsurrounding the particles (e.g., the carrier material/agent/sugarcomplex) to regulate release of the therapeutic agent. For example, theparticles may be coated with a polymeric coating (e.g., by spray-drying)an excipient such as cocoa butter to obtain a desired release profile ofthe therapeutic agent from the delivery vehicle. A polymeric coating maybe biodegradable or non-biodegradable, permeable or non-permeable torelease of the agent. One of skill in the art will recognize that it ispreferred for the polymer to be permeable, biodegradable, or both inorder for the agent to be released from the particles.

In certain embodiments, the particles of the composition may be coatedwith a range of polymers/solvents such as polyurethane, polysilicone,poly(ethylene-co-vinyl acetate), polyvinyl alcohol, polyanhydride,polylactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA),polyorthoester, polyalkylcyanoacrylate, polycaprolactone, derivatizedcellulose based polymers and derivatives and copolymers thereof, such aspolymethacrylate-based copolymers, to obtain a desired release profileof the therapeutic agent from the carrier material.

Methods of Use

In certain embodiments, the compositions are used to prevent or treat acondition of a patient. The various embodiments provided herein aregenerally provided to deliver a therapeutically affective amount of atherapeutic agent locally, i.e., to the site of the pain, disease, etc.,in a patient. In certain embodiments, the compositions of the inventionmay be delivered to any site on the surface or within the body of apatient. For example, compositions of the invention may used on thesurface of the skin or eye or may be implanted under the skin, within amuscle, within an organ, adjacent to a bone, within the eye or at anyother location where controlled release of a therapeutic agent would bebeneficial. The compositions may be administered intravitreally,subcutaneously, subconjunctivally, intraperitoneally, intramuscularly orsubretinally. In certain embodiments, the compositions of the inventionis delivered to the surface of the eye or within the eye such as withinthe sclera of the eye or within the vitreous of the eye.

In certain embodiments, the compositions of the invention are used totreat intraocular diseases, such as back of the eye diseases. Exemplaryintraocular diseases include glaucoma, age-related macular degenerationsuch as wet age-related macular degeneration, diabetic macular edema,geographic atrophy, choroidal neovascularization, uveitis, diabeticretinopathy, retinovascular disease and other types of retinaldegenerations.

In certain embodiments, the compositions of the invention are used totreat diseases on the surface of the eye. Exemplary diseases includeviral keratitis and chronic allergic conjunctivitis.

In certain embodiments, the method for treating an ocular conditioncomprises disposing the composition on the surface of the eye or withinthe eye such as within the vitreous or aqueous of the eye. In certainembodiments, the composition is injected or surgically inserted withinthe eye of the patient. In certain embodiments, the composition isinjected within the eye of the patient, e.g., into the vitreous of theeye. In certain embodiments, the composition is injected as acomposition. In certain embodiments, a composition comprises multiplecarrier material particles. The composition may comprise particles withan average size between about 1 micron to about 500 microns. In certainembodiments, the composition comprises particles with an averageparticle size between 5 microns and 300 microns such as between about 5microns and 100 microns.

In certain aspects, compositions of the invention may be used toadminister any therapeutic agent in a sustained fashion to a patient inneed thereof. The compositions of the invention are not limited toocular and intraocular use and may be used in any part of the body. Forexample, compositions of the invention may be used to administertherapeutic agents subdermally similar to the Norplant contraceptivedevice. In other embodiments, compositions of the invention are used toadminister biomolecules over a sustained period of time for thetreatment of chronic diseases such as arthritis. For example,compositions of the invention may be used to deliver therapeutic agentssuch as etanercept or adalimumab to patients in need of this therapy.The compositions of the invention may be located any place in the bodysuch as within a muscle. The composition may comprise multiple smallparticles such as multiple particles 500 microns or less. Thecompositions may comprise larger particles such as greater than 500microns or one or more particles greater than 1 mm in size such asgreater than 10 mm.

The therapeutic agent may be a small molecule or biomolecule. Thetherapeutic agent may be released to the patient over the course of upto four, six, or even up to twelve months after administration. In someembodiments, the therapeutic agent is released to the patient over thecourse of 1 month to 6 months. In preferred embodiments, the therapeuticagent is released to the patient over the course of 2 days to 2 weeks.In preferred embodiments, the therapeutic agent is released to thepatient over the course of 4 days to 12 days. In preferred embodiments,the therapeutic agent is released to the patient over the course of 6days to 10 days. In preferred embodiments, the therapeutic agent isreleased to the patient over the course of 7 days.

In certain embodiments, the composition is injected or surgicallyinserted subcutaneously. In other embodiments, the composition isdelivered to the patient intravenously or intraarticularly.

In some embodiments, the composition is administered orally. In someembodiments, the composition is orally administered and comprises avaccine. Oral administration can be used, for instance, to deliveractive agents to the stomach, small intestine, or large intestine.Formulations for oral administration may be in the form of capsules,cachets, pills, tablets, lozenges (using a flavored basis, usuallysucrose and acacia or tragacanth), powders, granules, and the like, eachcontaining a predetermined amount of an active ingredient. Solid dosageforms for oral administration (capsules, tablets, pills, dragees,powders, granules, and the like), may comprise the device and one ormore pharmaceutically acceptable carriers, such as sodium citrate ordicalcium phosphate, and/or any of the following: (1) fillers orextenders, such as starches, lactose, sucrose, glucose, mannitol, and/orsilicic acid; (2) binders, such as, for example, carboxymethylcellulose,alginates, gelatin, polyvinyl pyrrolidone, sucrose, and/or acacia; (3)humectants, such as glycerol; (4) disintegrating agents, such asagar-agar, calcium carbonate, potato or tapioca starch, alginic acid,certain silicates, and sodium carbonate; (5) solution retarding agents,such as paraffin; (6) absorption accelerators, such as quaternaryammonium compounds; (7) wetting agents, such as, for example, cetylalcohol and glycerol monostearate; (8) absorbents, such as kaolin andbentonite clay; (9) lubricants, such a talc, calcium stearate, magnesiumstearate, solid polyethylene glycols, sodium lauryl sulfate, andmixtures thereof; and (10) coloring agents. In the case of capsules,tablets and pills, the pharmaceutical compositions may also comprisebuffering agents. Solid compositions of a similar type may also beemployed as fillers in soft and hard-filled gelatin capsules using suchexcipients as lactose or milk sugars, as well as high molecular weightpolyethylene glycols and the like. The oral compositions can alsoinclude sweetening, flavoring, perfuming, and preservative agents.

In certain embodiments, multiple particle populations are delivered tothe patient such as two particle populations, three particlepopulations, four particle populations or five particle populations ormore. The particle populations may be substantially identical in size orcomposition or may have different sizes, a make up of different carriermaterials or be loaded with different therapeutic agents. The multipleparticle populations may be administered to the patient simultaneouslyor over a period of time, and at one or more locations of the patient'sbody.

In certain embodiments, the therapeutic agent is released from thecomposition into the surrounding biological system over a duration ofdays, weeks, months or years. In certain such embodiments, thetherapeutic agent is released over the course of time selected from oneday to two years, such as from two weeks to about one year, such asabout one month to about one year. The composition may release the druginto the eye over the course of 1 day to 12 months, such as 1 day to 6months, such as over the course of 1 week to 3 months. In certainembodiments, the therapeutic agent is released within two years, such aswith 18 months, within 15 months, within one year, within 6 months,within three months, or even within two months. In certain embodiments,the release of the therapeutic agent from the composition occurs in acontrolled manner such that a large percentage of the total impregnatedtherapeutic agent is not released immediately or within a short timespan, e.g., within minutes or hours of administration. For example ifthe desired drug delivery time is 2 months, the total impregnatedtherapeutic agent may, for example, be released at a rate ofapproximately 1/60th of the impregnated therapeutic agent per day. Incertain embodiments, controlled release involves the release of atherapeutic agent over the course of, for example, 1 month, 2 months, 3months, 4 months, 5 months, 6 months, 7 months, or 8 months, wherein theamount of the agent released charts linearly with respect to the fullcourse of delivery. In some embodiments, there may be a burst effect ofthe therapeutic agent shortly after administration, followed by asubstantially constant release over a subsequent period of time. Theburst effect may last, for example, from 1-10 days during which apercentage of the loaded drug is released. After the burst, theremainder of the therapeutic agent may be released constantly over acertain period of time. For example, in certain embodiments, less than10% of the therapeutic agent is released over the first day followingadministration, and a further 50% is constantly released over thesubsequent 2-30 days, e.g. at a substantially constant rate of release.In another exemplary embodiment, less than 10% of the therapeutic agentis released in the first 5 days following administration, followed byconstant release of 50% of the therapeutic agent over the subsequent 25days. By substantially constant release, it is meant that that rate ofrelease of the therapeutic agent from the composition is essentiallyconstant over a certain period of time.

In certain embodiments, the therapeutic agent begins being releasedimmediately after being administered. In certain embodiments, thetherapeutic agent is released over the course of approximately 3 to 8months, such as over the course of about 6 months. In certainembodiments, additional compositions of the invention are administeredto a patient at appropriate periods to ensure a substantially continuoustherapeutic effect. For example, successive doses of an composition thatreleases a drug for a period of six months may be administeredbiannually, i.e., once every six months.

The release of drug from the composition and into the body can beassessed by serum and vitreous analyses, e.g., using ELISA.

In certain embodiments, the composition may completely or partiallybioerode within a biological system. In certain embodiments, thecomposition may be resorbed by the biological system. In certainembodiments, the composition may be both bioerodible and resorbable inthe biological system. In certain embodiments, the carrier material maybe partially bioactive such that the material incorporates into livingtissue. In some embodiments, after implantation, the carrier materialdoes not substantially mineralize or attract mineral deposits. Forinstance, in some embodiments, the carrier material does notsubstantially calcify when placed in situ in a site where calcificationis undesirable.

In certain embodiments, the composition may bioerode in a biologicalsystem. In certain embodiments, greater than about 80% of the carriermaterial will bioerode in a biological system, such as greater thanabout 85%, greater than about 90%, greater than about 92%, greater thanabout 95%, greater than about 96%, greater than about 97%, greater thanabout 98%, greater than about 99%, greater than 99.5%, or even greaterthan 99.9%. In certain embodiments, where the carrier materialbioerodes, it is partially or completely resorbed.

In certain embodiments, the composition may substantially bioerode ofthe course of 1 week to 3 years. In certain embodiments, substantiallybioerosion refers to erosion of greater than 95% of the carriermaterial. In certain embodiments, substantial bioerosion occurs of thecourse of about 1 month to about 2 years, such as about 3 months to 1year. In certain embodiments, substantial bioerosion occurs within about3 years, such as within about 2 years, within about 21 months, withinabout 18 months, within about 15 months, within about 1 year, withinabout 11 months, within about 10 months, within about 9 months, withinabout 8 months, within about 7 months, within about 6 months, withinabout 5 months, within about 4 months, within about 3 months, withinabout 2 months, within about 1 month within about 3 weeks, within about2 weeks, within about 1 week, or even within about 3 days. In certainembodiments, where the carrier material bioerodes, it is partially orcompletely resorbed.

In certain embodiments, the extent of bioerosion may be evaluated by anysuitable technique used in the art. In exemplary embodiments, thebioerosion is evaluated through an in vitro assay to identifydegradation products or in vivo histology and analysis. Thebiodegradability kinetics of the porous carrier material may be assessedin vitro by analyzing the concentration of the principle degradationproduct in the relevant body fluid. For porous silicon-based carriermaterials in the back of the eye, for example, the degradation productmay include orthosilicic acid, quantified, for example, by the molybdateblue assay, and the body fluid may be simulated or real vitreous humor.The biodegradability kinetics in vivo may be determined by implanting aknown quantity of the porous silicon-based material into the relevantbody site and monitoring its persistence over time using histologycombined with, for example, standard microanalytical techniques.

EXAMPLES Materials Specifications of Commercial Porous Silica

Nominal Pore Size Surface Area Pore Volume Supplier Trade Name (Å)(m²/g) (mL/g) Grace Davison Davisil 60 550 0.9 Discovery 150 330 1.2Sciences 250 285 1.8 500 80 1.1 1000 40 1.1 SiliCycle SiliaSphere PC 300100 1.1

Example 1 Preparation of Sugar and Porous Silica Formulation

The co-formulations of mannitol, sorbitol or xylitol with 60 Å poroussilica (such as Davisil) can be achieved through melt loading.Approximately equal weights of silica and sugar are mixed by hand in azip-lock bag; then transferred to a suitable sample vial. The mixture isheated at the melting point of the sugar for a period of five minutes.

Example 2 Preparation of Trehalose and Porous Silica Formulation

The co-formulation of trehalose with 60 Å porous silica (such asDavisil) can be achieved through immersion loading. Approximately 1000mg of porous silica is immersed in 5 mL of a concentrated solution oftrehalose (500 mg/mL) and incubated for a period of two hours at roomtemperature and pressure, under continual agitation. This loadingsolution can be prepared using trehalose dihydrate crystals. Thestarting weight of these crystals must therefore be adjusted, so thatthe final concentration of the solution is approximately 500 mg/mL.Following incubation, the co-formulation is recovered from the loadingsolution via spin filtration using a PVDF filter (2 minutes at 13000rpm), frozen to minus 20° C. and freeze-dried. To preventre-crystallisation of the sugar during centrifugation, samples areheated to approximately 40° C. during this process. After the sugar hasbeen loaded, the formulation is dried.

Example 3 Preparation of Sucrose and Porous Silica Formulation

The co-formulation of sucrose with 60 Å porous silica (such as Davisil)can be achieved through immersion loading. Approximately 1000 mg poroussilica is immersed in 5 mL of a saturated solution of sucrose (2 g/mL)and incubated for a period of two hours at room temperature, pressureand under continual agitation. The sample is recovered via spinfiltration using a PVDF filter, frozen to minus 20° C. and freeze-dried.To prevent re-crystallisation of the sugar during centrifugation, thisprocedure is completed at a temperature of approximately 40° C. Afterthe sugar has been loaded, the formulation is dried.

Example 4 Preparation of Sucrose and Porous Silica Formulations

Bevacizumab (2 mL of a 1 mg/mL solution) was incubated with poroussilica 250 Å (e.g., Davisil) (40 mg) for 18 hours at room temperature.Sucrose (2 g) was added and the composition was incubated for 20 hours.After incubation the material was recovered via centrifugation through a0.45 μm centrifugal filter at 16,000 g. The composition was freeze-driedfor 18 hours.

A control formulation was prepared by freeze drying 100 μL of 1 mg/mLbevacizumab in phosphate buffer 50 mM pH 6.2 (without silica). Abevacizumab-sucrose co-formulation control was also prepared by freezedrying 100 μL of 1 mg/mL bevacizumab and 300 μL 1 g/mL sucrose inphosphate buffer 50 mM pH 6.2.

After drying, triplicate samples of each composition were extracted with200 mM carbonate buffer pH 9.6 for 6 hours. After extraction the sampleswere centrifuged and the supernatant assayed via SEC to assay forrecovery of bevacizumab. Results are shown in FIG. 2.

Example 5 Preparation of Formulations Comprising Sucrose and MesoporousOxidized Anodized Silicon Material

Mesoporous oxidized anodized silicon material, as disclosed in U.S. Pat.No. 8,318,194 and U.S. 20120177695, was successively incubated withbevacizumab and sucrose as disclosed herein, followed by vacuum dryingto remove excess water. Results are shown in FIG. 2.

Example 6 Release of Myoglobin from Polymer-Coated Particles

Mesoporous oxidized anodized silicon material (60 Å) was loaded withmyoglobin and sucrose in analogy to the previous examples and the loadedparticles were coated with PLA or PLGA. Release of myoglobin from thesecoated particles is depicted in FIG. 3.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, numerous equivalents to thecompounds and methods of use thereof described herein. Such equivalentsare considered to be within the scope of this invention and are coveredby the following claims. Those skilled in the art will also recognizethat all combinations of embodiments described herein are within thescope of the invention.

While the above described embodiments are in some cases described interms of preferred characteristics (e.g., preferred ranges of the amountof effective agent, and preferred thicknesses of the preferred layers)these preferences are by no means meant to limit the invention. As wouldbe readily understood by one skilled in the art, the preferredcharacteristics depend on the method of administration, the beneficialsubstance used, the shell and carrier materials used, the desiredrelease rate and the like.

All of the foregoing U.S. patents and other publications are expresslyincorporated by reference herein in each of their entireties.

1-33. (canceled)
 34. A method of treating or preventing a condition in apatient comprising administering to the patient a composition comprisinga bioerodible porous silicon-based carrier material, wherein the carriermaterial comprises at least one large-molecule therapeutic agent and anamorphous sugar.
 35. The method of claim 34, wherein the composition isadministered to the surface or the skin or eye of a patient.
 36. Themethod of claim 34, wherein the composition is administeredintravitreally, subcutaneously, subconjunctivally, intraperitoneally,intramuscularly or subretinally.
 37. The method of claim 34, wherein thecomposition is administered into the eye.
 38. The method of claim 37,wherein the composition is administered within the aqueous of the eye.39. The method of claim 37, wherein the composition is administeredwithin the vitreous of the eye.
 40. The method of claim 34, wherein thecondition is selected from conditions of the eye.
 41. The method ofclaim 40, wherein the condition is selected from glaucoma, maculardegeneration, diabetic macular edema, geographic atrophy and age-relatedmacular degeneration.
 42. The method of claim 34, wherein thecomposition releases the therapeutic agent into the eye over the courseof 1 day to 6 months.
 43. The method of claim 42, wherein thecomposition releases the therapeutic agent over the course of 1 week to3 months.
 44. The method of claim 34, wherein the porous silicon-basedcarrier material is contacted with a solution comprising the therapeuticagent. 45-50. (canceled)
 51. The method of claim 34, wherein the carriermaterial is resorbable.
 52. The method of claim 34, wherein thetherapeutic agent is selected from proteins, peptides, antibodies,carbohydrates, polymers and polynucleotides.
 54. The method of claim 52,wherein the therapeutic agent is an antibody.
 55. The method of claim34, wherein the amorphous sugar is selected from trehalose, trehalosedihydrate, sucrose, mannitol, sorbitol, xylitol and glycerol, or acombination thereof.
 56. The method of claim 34, wherein the carriermaterial has a porosity in the range of about 40% to about 80%.
 57. Themethod of claim 34, wherein the average pore size is in the range 2-50nm.
 58. The method of claim 34, wherein the average width of the wallsin the carrier material which separate the pores is less than 5 nm. 59.The method of claim 34, wherein a length of the carrier materialmeasured at its longest point is between 1 and 500 microns.
 60. Themethod of claim 34, wherein the load level of the carrier material isless than 80% by weight based on the combined weight of the carriermaterial and therapeutic agent.